Cancer charity Macmillan says 6,000 cancer patients are “dying needlessly” due to an apparent “postcode lottery” in the NHS in England.

It says there are huge regional variations in cancer survival rates, and warns that we need to be looking at how different health service areas are dealing with the illness.

“The alarming postcode lottery of cancer survival in England could be explained by how quickly patients are being diagnosed and treated,” Macmillan said in a press release.

What difference does it make where you live?

The proportion of people surviving for at least a year after being diagnosed with cancer varies from 61.8 per cent to 76.2 per cent depending on where they live, according to Office for National Statistics (ONS) data.

While there will always be some natural variance in these kind of figures, that’s a pretty big difference between the best and worst-performing NHS area, now called clinical commissioning groups (CCGs).

The worst-performing group was Barking and Dagenham in east London. The best was North East Hampshire and Farnham.

You can read the full list here.

It probably goes without saying but this doesn’t mean an individual patient in Barking who has just been diagnosed with cancer has a 61.8 per cent chance of surviving more than a year.

These are averages drawn from massive amounts of population data, taking in people who have many different kinds of cancer, and every case will be different.

So is this all about money?

No. It happens to be the case that a deprived outer London borough has the worst survival rate and a leafy part of south east England has the worst, but that is something of a red herring.

Affluent parts of Kent, West Sussex and Cheshire have some of the worst survival rates, while parts of Leeds and Manchester are among the best performers.

Socio-economic factors can’t explain the variation in survival rate, as the ONS adjusts for deprivation (as well as age, sex and region) when it calculates these figures.

The whole point of this data set is that it is supposed to filter out the effect of the background of patients in order to focus on the quality of the care they receive.

This study, which focuses on what happens to cancer sufferers after they are diagnosed, is not to be confused with research into how many people get cancer in the first place.

These studies do tend to find strong links between socio-economic deprivation and cancer, probably because poor people lead less healthy lifestyles.

Is it fair to blame the NHS?

Probably. Macmillan finds a correlation between poor survival rates and one of the NHS’s performance targets: that 85 per cent of patients should begin treatment within 62 days of an urgent GP referral.

The worst-performing 20 per cent of CCGs managed an average of 83.1 per cent – missing the target – in the last quarter of 2013/14, while the top fifth scored 86 per cent.

It’s possible that factors unrelated to the quality of care – like the time it takes people to go the GP to get their symptoms checked out – are important too.

Are 6,000 people a year really “dying needlessly”?

It depends how you look at it. What this means is that if every CCG did as well as the top performer, 5,900 more people would survive for more than a year.

Of course even if there were massive improvements in survival rates and we ironed out most of the regional differences, there would still be some natural variance in the figures.

You could always say that some people were “dying needlessly” because not every CCG performed as well as the best one.

Is there any good news?

Overall, cancer survival rates are improving fairly rapidly. The one-year rate for England increased from 59.2 per cent for patients diagnosed in 1996 to 68.2 per cent in 2011.

Unfortunately the UK and Ireland lag behind other European countries for some of the most common kind of cancers.

Last year the Eurocare 5 study, which tracked cancer survival rates across Europe, found UK and Ireland survival rates were lower than the European average for breast, colon, lung, prostate and ovarian cancer. The rate was better than average for melanoma.

This study did not allow for socio-economic and lifestyle factors so it can’t be read as an indictment of NHS care. It could be that smoking, diet, and other factors are more important than the quality of treatment.